$A$ methyl group attached to a benzene ring can be oxidized to a carboxyl group by reacting with:

In the reaction sequence $CH_3-C \equiv CH$ $\xrightarrow{CH_3MgBr, \text{Dry ether}} CH_4 + (A)$ $\xrightarrow[(i) \ CO_2]{(ii) \ H_2O/H^+} (B)$,$(B)$ will be

Which among the following reactions forms acid anhydride?

Which of the following reagents is the correct sequence for the conversion of $R-CH_2-CH_2OH$ to $R-CH_2-CH_2-COOH$?

Identify product $C$ in the following conversion sequence: $m$-Hydroxybenzaldehyde $\xrightarrow[\text{Protection of } -OH \text{ group}]{C_6H_5CH_2Cl} A$ $\xrightarrow{[O]} B$ $\xrightarrow{\text{deprotection}} C$.

Which among the following compounds is $NOT$ used for the preparation of aromatic carboxylic acids from alkyl benzene?